Cellulose-ether composition



Patented Nov. 12, 1929 UNITED STATES PATENT OFFICE STEWART J. CARROLL, OF ROCHESTER, NEW YORK, ASSIGN'OR T EASTMAN KODAK COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK GELLULOSE-ETHER COMPOSITION No Drawing.

instance as sheet or film manufacture and varnish manufacture.

One object of the invention is to provide a composition which ,may be made into permanently transparent, strong and flexible sheets or films of desired thinness, which are substantially waterproof, are unaffected by ordinary photographic fluids, and possess the desired properties of a support for light-sensitive photographic coatings. Another object of my invention is to produce a compositioncapable of easy manipulation in the plastic'and film making, or varnish making, or allied arts; but will not injure or be injured by the substances with which it is associated during manufacture, storage or use. Still another object of my invention is to provide a film having the hereinabove described properties. Other objects will hereinafter appear.

I have found that a composition having the desirable qualities hereinabove enumerated can be obtained by mixing or compounding cellulose ether, say for example an alkyl ether of the type described in U. S. Patent No. 1,188,376, June 20, 1916, Leon Lilienfeld, with ethylene glycol diacetate. This mixing to a colloidized stateis preferably performed with the aid of a common solvent. While the details of one way of carrying out my invention will be given by way of example, it will be understood that my invention is not restricted thereto, except as indicated in the appended claims. It is an inherent characteristic of ethylene glycol diacetate that it has substan-' Application filed October 7, 1925. Serial No. 61,140.

In carrying out one embodiment of my invention, 100 parts of water-insoluble ethyl cellulose are dissolved along with from 5 .to parts of ethylene glycol diacetate (say 20 parts) in from 300 to 500 parts of a volatile common solvent. The latter may usefully comprise a mixture of methyl acetate and methyl alcohol, the weight of methyl acetate being approximately nine times the wei ht of the alcohol. This composition is suita lole for spreading upon a film-forming surface in a coating, from which the volatile solvent evaporates sufliciently to lea've at-ransparent flexible sheet, which is stripped off and otherwise treated in the way well known in this art. The parts are by weight. The transpare'ncy and flexibility of the sheet demonstates that the cellulose ether and the ethylene glycol diacetate in it remain in a coll0idized state without precipitating each other.

lVhere a more readily fiowable composition is desired, the amount of volatile solventmay be increased until the desired results are obtained. Benzol and ethyl or methyl or methyl alcohol may be added in'thinning it out. Of course, other equivalent volatile solvent mixtures may be substituted. Moreover, ingredients which impart characteristic properties to the film may likewise be added, such as triphenyl phosphate, tricresyl phosphate, camphor, monochlor-naphthalene, etc. The proportions of these substances, or mixtures of them, should not be suflicient to cause precipitation of the ether, or to cause white films or varnish coatings to be produced. The ingredientsare of the commercial type and sufficiently purified for ,the ends in view. Where the dope is to be made into sheets or films for photographic purposes, the substances are chosen or purified to have the proper relative freedom from color.' Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

As an article of manufacture, a film comprising Water-insoluble alkyl cellulose and ethylene glycol diacetate, said film being formed from a composition containing from 5 to 50 parts by Weight of said ethylene gylcol diacetate to each parts of alkyl cellulose, the proportions of the ingredients being such that the film is flexible and transparent.

Signed at Rochester, New York this 30th day of September, 1925.

STEWART J. CARROLL. 

